A low-carb diet restricts daily carbohydrate intake to under seventy-five carbohydrate grams per day regardless of the number of calories consumed. For weight loss, the recommended carbohydrates are between 20 and 50 grams. A diet that recommends 40-60% carbohydrate calories is not a low-carb diet.
There are a number of low-carb diet plans on the market today, each of which has a particular approach to low-carb eating. Some of the books and their plans are silly; others present a combination of scientific and pseudo-scientific explanations for their program, while still others make their recommendations based upon valid research findings. Not all of the published diet plans that call themselves “low-carb” fit the basic requirements of a low-carb diet.
Types of restricted carbohydrates
High on the restricted list of carbohydrates are the simple sugars (glucose, sucrose, lactose, and dextrose) and anything made with them such as ice cream, cake, cookies and pie. This list includes fruit juices.
Second on the restricted list are the grains – wheat, corn, rice – and all foods made with them such as corn chips, breakfast cereals, breads, pastas, and crackers.
Third are the “complex carbohydrates” such as potatoes, corn, and beans (except green beans).
The reason for restricting carbohydrates
The underlying principle upon which low-carb diet plans were developed is that the hormone insulin is a fat storage hormone. Our bodies always have some insulin floating around to keep our blood glucose/blood sugar within a very narrow range. The usual estimate is about one teaspoon. When we eat anything that raises our blood sugar/glucose, insulin is secreted to control that influx of sugar. Depending upon how much sugar we take in at a time (how many grams of carbohydrate) and how often in a day we eat or drink carbohydrates, our pancreas has to work constantly to keep our blood stream clear of excess glucose.
Simple sugars (candies, cookies, cakes, muffins, ice cream, fruit juices) are released quickly into the blood stream creating a surge of insulin to control it. The more simple sugar ingested, the more insulin is needed to control the upsurge of blood sugar. The combination of a simple sugar eaten in a large amount at any one time creates a massive surge of insulin to control in influx of blood sugar.
The complex carbohydrates (grains, legumes, and starchy vegetables like potatoes) are not immediately converted into blood sugar in the stomach. They tend to pass through the stomach more slowly because of the fiber content and are often absorbed in the small intestine. The amount eaten, however, like the simple sugars, dictates the amount of insulin needed to control the resulting rise in blood sugar.
The primary way the body handles excess blood sugar is to store it in fat cells. Insulin affects every organ of the body. When our bodies are awash with insulin to correct our “carbohydrate fix” we are seriously undermining every other organ in our bodies. Over time, as we grow older, we pack on the weight, develop diabetes, hardening of the arteries, high blood pressure, high cholesterol, fatty liver disease and heart disease.
Which carbohydrates are allowed on a low-carb diet?
A wide variety of fruits and vegetables are allowed in a low-carb diet. Concentrate on the fruits and vegetables with the lower sugar content. The sweeter the fruit, the higher the sugar concentration. Milk and milk products all contain carbohydrates but are rich in protein.
Amount of protein in a low-carb diet
Low-carb diets are frequently and erroneously labeled as “high protein” diets. Low-carb diets don’t work that way. Almost any diet will recommend 30% of your calories as protein (unless you have a health problem that requires limiting protein). When you are on a low-carb diet, the only thing that changes, besides your carbohydrates, is your fat content. When carbohydrates go down, fats go up. Proteins stay the same.
Fat content in the low-carb diet
Low-carb diets do not limit the amount of fat you eat, whether the fat is saturated or unsaturated. Foods containing Trans-fats (also called “partially hydrogenated” fats) are forbidden absolutely.
Since all protein foods contain fat content, the choice of protein affects the amount of fat in the diet. Beef has a higher fat content than pork, fowl, fish or game. The choice of animal protein determines the amount of fat you will eat in a meal. Milk and milk products contain fat unless they are processed to be fat free. Milk products, however, also contain carbohydrates. To lose weight more quickly, select your proteins from the lower fat choices without increasing the carbohydrate count.
Combination foods
Many foods are combinations of protein, fat and carbohydrate. Milk and milk products are a good example. Manufacturers may advertise a lower fat alternative, so check the labels to be sure the carbohydrate content has not been increased to compensate for the lack of fat. Yogurt is a good example of a low-fat product that has added carbohydrate. Cottage cheese and milk, on the other hand, only reduce the fat without adding carbohydrates. Soy beans, and their products, are also a combination of protein, fat and carbohydrate.
Most protein sources are a combination of protein and fat. If a food contains any protein at all, it is classified as a protein no matter how much fat it contains. Nuts are a good example of a very high fat food with some protein.
What is a low-carb diet?
The basic requirement of a low-carb diet is that the diet must have less than 75 grams of carbohydrate in a day, no matter how many calories you eat.
References
The Atkins Diet Revolution and New Diet Revolution
Dr Johnny Bowden. Living the Low Carb Life. 2004.
Comparison of the Atkins, Zone, Ornish and LEARN Diets for change in weight and related risk factors among overweight premenopausal women: the A – Z Weight Loss Study: A Randomized Trial. Journal of the American Medical Association. March 7, 2007; Vol. 297: 969-77.
Drs Michael and Mary Dan Eades: Protein Power (1999), Protein Power Life Plan (2001), The 30 Day Low Carb Solution (2002) The 6 Week Cure for the Middle Aged Middle (2009)
Dr Rob Thompson. The Glycemic Load. Diet. 2006.